[llvm] [SLP] Use costing to decide between Strided Loads and Compressed Loads (PR #226540)

[Alexey Bataev via llvm-commits]

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@@ -40,6 +43,34 @@ enum class RecurKind;
 
 namespace llvm::slpvectorizer {
 
+/// Returns \p Stride scaled by the allocation size of \p ScalarTy, negated if
+/// \p IsReverse is set, or nullptr if \p Stride is not a constant.
+ConstantInt *getStrideBytesIfConstant(Value *Stride, Type *ScalarTy,
+                                      const DataLayout &DL,
+                                      bool IsReverse = false);
+
+/// Return the cost of a strided load and accompanying bitcast.
+InstructionCost getStridedLoadCost(const TargetTransformInfo &TTI,
+                                   const DataLayout &DL, Value *StrideVal,
+                                   Type *StridedLoadTy, Type *VecTy, Value *Ptr,
+                                   Align CommonAlignment,
+                                   TargetTransformInfo::CastContextHint Ctx,
+                                   TargetTransformInfo::TargetCostKind CostKind,
+                                   bool IsReverse = false);
+
+struct CompressedLoadInfo {
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alexey-bataev wrote:

Add a description to this new structure

https://github.com/llvm/llvm-project/pull/226540